Motor control apparatus



April 13, 1954 R. c. RUHLAND MOTOR CONTROL APPARATUS Filed Feb. 24, 1953INVENTOR. ROMAN G. RUHLAND ATTORNEY Patented Apr. 13, 195 4 UNITEDSTATES PATENT OFFICE MOTOR CONTROL APPARATUS of Delaware ApplicationFebruary 24, 1953, Serial No. 338,459

My invention relates to improvements in motor control apparatus and inparticular to the type of motor control apparatus disclosed in thecopending application of Robert J. Kutzler, Serial No. 310,066 filedSepteember 17, 1952, wherein speed control of the motor is obtained byapplying pulsed increments of electrical energy to a motor. 7

Control of the speed of operation of an electric motor through thevariation in the amount of energizing power th motor receives is anaccepted process, particularly in the field of direct current motors.Speed control through the application of pulsed increments of power haspreviously been accomplished such as in the above mentioned Kutzlerapplication. Up to the present time, however, the known methods andapparatus for controlling the speed of operation of electric motors haveall proved inadequate for certain applications in that they lackcomplete uniformity of control over the entire speed range of operationof the motor. This is particularly true where linearity over the entirespeed response range of operation is desired. The application of pulsedincrements of power through the apparatus disclosed in the above namedKutzler application, attempts to solve this problem by varying thepulsed increments of power and the frequency at which they are applied,but fail to adequately control the motor at lower ranges of speed.Therefor it is an object of this present invention to provide animproved motor control apparatus of the type disclosed in the abovenamed Kutzler application which will provide any desired response overthe entire operation of a motor.

It is also an object of this invention to provide in a motor controlapparatus means for varying the pulsed increments of power supplied to amotor armature for speed control purposes by controlling the period oftime during which the power is supplied to the motor, the period of timeduring which the motor is deenergized and the frequency of the pulsedapplication of power to the motor.

It is further an object of this invention to provide an improved motorcontrol apparatus with linearity of response or speed torque curves overthe entire range of operation.

It is also an object of this invention to provide in an improved motorcontrol apparatus of the pulsing relay type controlled primarily by aprimary controller with additional resistance-capacitance circuits whichare energized when power is applied with the motor armature and 19Claims. (Cl. 318257) a which cooperate with the primary controller andthe motor armature to form a discharge path through the operating coilsof the pulsing relay to modify the effect of the primary controller andthereby vary the increments of power supply to the motor.

These and other objects of this invention will become apparent from areading of the attached description together with the drawing.

My invention, as indicated above, relates to improved motor controlapparatus of the type disclosed in the copending application of RobertJ. Kutzler 'which is of the pulsing relay type. Referring to thedrawing, it will be seen that my improved pulsing relay circuit includesan armature H) of the motor to be controlled, directiontal fieldwindings I! and [2 of the motor,

-contact mechanism or circuit closure means l3 in the form of a movablecontact i5 and a stationary contact IS, an energizing coil I! for therelay, the electromagnetic structure which is not shown and a primarycontroller or potentiometer 20. This system is energized from a D. C.source of power, which is generally shown at 25, having buss bars 26 and21 connected thereto. Armature ID of the motor whose speed is to becontrolled is energized through an energizing circuit from the plus sideof the source 25 through conductor 21 to a pair of directional switches30, 3| connected to directional field windings I I and I2, armature ID,to a resistor 32 and conductor 33 to stationary contact I6 of relay I3,and from movable contact I5 to conductor 34, buss bar 26 to the negativeside of the supply. The operation of the relay or its contact means 15and It to close this energizing circuit and supply power to the motorarmature is controlled primarily by the energization coil ll of therelay. Relay coil I! is energized through from the primary controller 20which includes a potentiometer winding 40, center tapped at 4|, andhaving a wiper 42 in operative association therewith. The extremities ofthe winding are connected together by conductors 44 and 45 with thecommon extremity of the winding being connected to buss bar 26 by aconductor 41, resistor 48, and conductor 49. Potentiometer winding 49 isconnected to the opposite side of the source or buss bar 2! at itscenter tap 4! through a conductor 50, dead spot resistor orpotentiometer 5| and conductor 52. It will be noted that the extremitiesof the potentiometer winding are connected together to a common side ofthe source therefore being energized at the same potential while thecenter tap is connected to the opposite side of the source of powerconsequently providing an arrangement in which each half of thepotentiometer winding is similarly energized and in the same directionor with the same electrical polarity. Mechanically connected to thepotentiometer wiper 42 through a mechanical connection indicated at 55are the field switches 30 and 3| one of which will be operative when thepotentiometer wiper 42 moves to on side of the center tap 4| and theother operative when the potentiometer wiper 42 moves to the oppositeside of the center tap 4|. This basic circuit becomes operative when thepotentiometer wiper is moved to one or the other side of thepotentiometer winding 48 from the dead spot 4| placing the signalpotential from controller 20 on the coil l! which is connected to thewiper 42 through a pair of single pole, double throw switches 60 and BI,the purpose of which will be explained as the description proceeds. Forthe present purposes of explanation, it will be assumed that theseswitches will not part from their operating position and consequentlythe coil will be connected from the wiper 42 through switch 60 in itsnormally closed position, through switch 6| in its normally closedposition to conductor 62, coil conductor 63, resistor 64, conductor 65,to armature l and ar mature Hi through field windings I, I2, switches3|, 32 and conductor 27. Movement of the wiper from either side of thepotentiometer center tap 4| will cause current to flow from theconductor 21 through this energizing circuit to coil l1 andpotentiometer wiper 42, potentiometer winding 40, conductors 44, 45,conductor 4T, resistor 48, conductor 49 and buss bar 26. Current willthen flow through the relay coil and when the current flow has reachedthe point where the relay will pull in, the contacts [5 and H5 will beactuated to a closed position supplying power to the energizing circuitof the motor from buss bar 21, switches 38 or 3|, winding H or l2,armature l0, resistor 32, conductor 33, contacts l5 and I6, conductor 34to buss bar 25.. It will be appreciated that one or the other of theswitches 30 and 3| will be closed as soon as the potentiometer departsfrom the center tap point through operation of the mechanical connection55. Current fiow through the coil operates to close the relay contactsl5, I6 which sets up a second energising circuit for the relay coil inthe direction tending to urge the contact mechanism toward the out oropen position. This circuit extends from buss bar 21, to conductor 52,dead spot resistor 5|, conductor 58, potentiometer winding 40, wiper42-, switches 60 and BI, conductor 62, coil H, a condenser 10, conductorH, rectifier I2, conductor 33, contacts l5, l6, conductor 34, to bussbar 26. The purposes of the condenser 10 and rectifier 12 as well as thedead spot resistor 5| will be described in detail as the disclosureproceeds but for the present it may be considered that they merely serveto connect this circuit through the contact mechanism or relay l3 tobuss bar 26 for the purpose of energizing the relay coil in an outdirection. Energization in this direction will have caused the relay toopen terminating this second or energizing circuit for the relay as wellas the energizing circuit for the motor and leaving only the first namedenergizing circuit for the relay coil I! in the opposite direction whichwill tend to cause the relay to pull in and repeat the cycle. Movementof the wiper 42 away from the center tap 4| will decrease the impedancein the. ener- 4 gizing circuit for the coil H in the in direction andincrease the impedance for the coil H in the out circuit path or in thecircuit tending to energize the coil and urge the contacts to the openposition. Under these conditions, the relay contacts will stay in theclosed position longer because of the greater time required to build upenough current in the out direction for the energization of the coil ITin the second named energizing circuit. With the relay contacts made forlonger percentage of time, the average current through the motor willincrease and consequently the motor will run faster. A certain amount ofspeed regulation is inherent in this system in that th back E. M. F. orcounter E. M. F. of the motor will decrease the in current as the motorapproaches the speed called for by the position of the potentiometerwiper 42 on winding 40. When the wiper 42 is set in a certain position,the current tending to pull the relay in will have a certain valuebefore the motor begins to rotate. As the motor starts to rotate andbuild up speed its effective impedance will increase due to the counterE. M. F. of the armature and reduce the current in the energizingcircuit for coil H which includes the armature H1 or the circuit tendingto pull the relay in. Thus as motor speed picks up, the current tendingto open the relay does not have to build up to as high a value as itwould if the motor were not turning in order to drop out the relay. Itwill also be seen that if the motor were to become loaded it would notturn as fast and less counter E. M. F. would be generated, thus therelay would tend to hold in longer increasing the average motor currentand the motor will have increase in torque.

Two directional control of the motor is achieved through operation ofthe switches 3| and 32 and the energization of the coils II and I2 whichare selectively energized depending upon the position of the wiper 42 onthe winding 40 or the direction of operation of the primary controlleror potentiometer 2|). In the present disclosure, the field windings areconnected in series with the motor armature but it should be understoodthat they may be separately energized in the parallel circuitindependent of the armature if desired. With the potentiometer windingidentical in both directions due to the center tapping and theenergization of the potentiometer at the center tap and the commonextremities, identical portions are obtained on the potentiometerwinding and handle or wiper displacement in either direction will.produce identical motor response but in opposote directions due to theopposite or selective energization of the field coils. The dead spotresistor 50 which is included in this circuit provides for minimum speedcontrol and is placed there toeliminate electrical dead spots in thepotentiometer 20. Should the tap connection be connected directly to theplus side of the supply or to buss bar 21 the wiper 42 would have to bemoved a predetermined distance before enough current would flow throughthe relay coil I"! to actuate the contact mechanism. By adding avariable resistance between the center tap 4| and the buss bar 21 thispoint is placed at a potential below the potential of the buss bar 26and is adjusted so that very slight displacements from th center tap 4|by the wiper 42 will produce suiiicient voltage across the coil I! toactuate the contact mechanism l3.

It will also be noticed that. the field windings II and 12 are connectedthrough a conductor 15 and a resistor F3 to buss bar 26 in a circuitwhich shunts the armature l and relay contacts and Hi. This circuit withits resistance is provided simply to insure current to the motor fieldswhenever the switches 30, 3| are actuated. The amount of currentsupplied by this circuit improves the motor characteristics and providesfor increased speed torque regulation.

Relay I3 is also provided with a coil Tl which is energized from bussbar 2! through a conductor 78, condenser 79, conductor 80, conductor 8!,coil 17, conductor 82 to conductor 33, contacts i5 and I6, conductor 34to buss bar 26. This second relay coil is provided to obtain goodcontact operation with positive contact closure and opening of thecontact mechanism l3. The condenser 19 is provided in series with thiscoil to provide a high transient surge through the coil. However, thiscircuit has no initial effect on the operation of the relay until afterthe contacts 15 and It have closed and energization of the coil is insuch direction as to slam or urge the contacts l5, it into furtherengagement in a snap action type of operation making good contacttherebetween. Besides increasing the contact closure characteristics ofthe contact mechanism, the condenser 19 and the coil Ti further tend toincrease the on time of the relay. When the contacts I5, I6 open,condenser 19 discharges through a path which includes the switch 38 or3|, field windings II or 52, armature l0, resistor 3B, conductor 82,coil 11, conductor 8! and conductor 39 to the condenser is whichdischarge energizes coil ll in a circuit opening direction to providefor snap action of the contact mechanism in the opening direction. Inorder to provide for very low speeds when the wiper 42 is displaced veryslightly to the center tap M on winding 49, the on time or" the relaymust be held to a very short period. The inclusion of condenser andresistor 64 in the energizing circuit of coil ll both in the in and outdirections serve this function. The condenser 10 which is included inthe energizing circuit in series with coil IT for energization of coilI! when the contacts and I6 of the relay are closed and which energizesthe coil toward the out direction provides for a high transient path inthis direction which current flow tends to drop out the relay. Thus theinstant the contact is closed, this condenser 10 has the effect ofcausing them to open immediately and overcome the tendency of thecondenser i9 and winding ll when the contacts are closed to hold therelay contacts closed for a longer period of time. The resistance 64which is included in the energizing circuits of the coil l I andconnected between the coil I 1 and the armature I0, in circuit toenergize the coil in the in direction, serves as a current block toprevent too great a portion of transient current to the condenser H!from passing through the motor instead of coil ll. Both of the circuitsinvolving the condensers l0 and 79 are RLC circuits. The time constantof such a circuit is proportional to the resistance of the circuit.

after the relay has slammed in and overcome the tendency to hold in fortoo long a period of time. As the wiper 42 is moved up the potentiometeror away from the dead spot 4|, that is greater on time being called for,the resistance of the RLC circuit of condenser 19 is increased and thetime constant is likewise increased thereby decreasing the effects ofthe condenser it. Its effect is greatest at low displacements of thepotentiometer wiper 42 where such action is desired. The action of coilII in the discharge circuit of condenser 19 always insures positivecircuit opening or snap action of contacts l5, H3 in the open direction,however. At the same time that a very short on time of the relay isobtained, it is desirable to have a long ofi time or circuit openposition of the contacts 15 and Hi. If the off time is short then the ontime pulses have to be very small to reduce the average current throughthe motor and consequently the motor speed. To obtain the long ofi time,a condenser E l, resistor 85, and the rectifier 72 have been added tothe circuit. Condenser 84 is connected to buss bar 21 through aconductor 88 and through a conductor 8'! to one side of the condenserTil, resistor 85 and conductor H. The resistor 85 is connected at itsopposite extremity to conductor 63 and the opposite side of condenser10. Rectifier 12 as previously indicated is included in series with thecondenser '19 and contacts [5 and It in the energizing circuit for coil1'. which tends to energize the coil I! in the out direction. When thecontacts [5 and it are made, the condenser 84 charges through a circuitfrom buss bar 27, conductor 86, condenser 84, conductor 81, conductor H,rectifier 12, conductor 33, contacts 15 and I6, conductor 34, to bussbar 25. When the contacts l5, 86 are opened, the rectifier 12 preventsdischarge of the condenser 84 through a circuit including motor armaturel0 and resistor 32 and consequently the condenser 84 must dischargethrough the dead spot resistor 5| a portion of the potentiometer winding40, coil I! in a direction to hold the relay out, and due to the highresistance in the discharge path this circuit has a high time constant.This discharge circuit extends from condenser 83, conductor 86, buss bar21, conductor 52, resistor 5|, conductor 5Q, winding 40, wiper 42,switches 60, 6!, conductor 62, coil ll, conductor 63, resistor 85,conductor H, conductor 8? to the condenser 84.

Thus at low displacements of the potentiometer wiper 42 on winding M1,the current in the in direction is small and the discharge current ofcondenser 84 tends to hold the relay l3 open for a relatively longperiod of time. As the handle is displaced more from the center tap 4|on the winding 40, the in current becomes greater and tends to overcomethe effect of the condenser 84.

As previously explained, the basic circuit has a certain amount ofinherent speed regulation. In order to increase this speed regulationand to exercise further control over the same, an adjustable resistance96 is added to the control circuit, this resistor being connectedbetween the armature l6 and conductors 8%, 3! connecting the resistor tocoil F1. The resistor 96 provides a shunt path across the resistor 32and provides for a certain current flow through the coil 1! the amountbeing regulated by the value of the adlustable resistance 8%. Thiscurrent flow is in a direction to make the relay hold in longer, that isit energizes coil 7? in the same direction as the energizing path forrelay coil I1 through the condenser 19. .It can be, readily seen that asthe current to resistor 32 increases so will the current to coil 11.Thus, if the motor slows. down as the load increases with givendisplacements of the wiper 42 of the primary controller 20, the counterE. M. F. generated at the motor armature will decrease and the currentthrough resistor 32 and coil TI Will increase. This will increase the ontime of the relay I3, that is, provide for a longer closure of contactsI5 and I6 and a greater average of current to the motor armature I0,consequently increase the motor torque toovercome the loading.

An arc suppression circuit indicated at BI and including condenser 92,93 and a resistance 94 are connected across the contacts I5 and I6 toprevent material transfer or pitting of the contacts. This arcsuppression circuit is conventional and forms no part of the presentinvention.

It will be seen thus far that operation of the primary controller, thatis the movement of the wiper 42 on the winding 40 acts initially toenergize the coil of relay I! in the in direction causing the contactsI5 and It to close and the motor armature to be energized andsimultaneously therewith the closure of one or the other of the contacts30, 3| for the field winding I I, I2 to permit energization to the fieldwindings to control the direction of rotation of the motor. Thepotentiometer 20 serves further as an adjustment in an RLC circuit todetermine the effect of the additional energizing circuit on the coil I1of the relay varying the period of time during which the relay contactmechanism is pulled in, the period of time during which the relaycontact mechanism is dropped out and the frequency at which the relaypulses. The circuitry for the coil H for both the in and outenergization thereof was completed in part through the in contacts ofswitches 60, 6|, which are to be identified as slewing or fast speedswitches. The switches are shown herein as single pole double throwswitches operatively connected to the wiper of the potentiometer 42 foroperation therewith. The stationary portion of the out contacts of theseswitches are identified as I and IIlI and are connected together at acommon point by conductors I02, I93 and to the buss bar 26 by conductorI04. These slewing switches are designed to be operated only when thewiper 42 is displaced over a predetermined range of displacement of thewiper on the potentiometer winding from the center tap 4|. Thispredetermined displacement as shown herein to be maximum displacement ofthe wiper 42 on the winding 40 at which point one or the other of theswitches 60, 6| will be operated depending upon the direction ofmovement of the wiper 42 to engage the respective out contacts I 00 orIOI and set up an auxiliary shunting circuit around the primarycontroller through the conductor I04 from buss bar 26 and conductors I0201' I03, contacts I06 or IOI and the remainder of switches 60 or 6| toconductor 62 and coil I! of the relay I3. Thus, when the slewingswitches or high speed switches are actuated, the relay coil is switchedfrom the wiper of the potentiometer or controller 20 directly to thenegative line or buss bar 26 and the relay pulls in solid resulting inmaximum speed of the motor. Slightly greater sensitivity for the primarycontroller 2D is obtained by the use of the resistor I05 which isconnected at one extremity to the buss bar 26 and at its other extremityto center tap 4| of winding 40 in that its results as a shunt across thepotentiometer 20 and resistance 48 which is in series relation therewithmaking it possible to use lower values of resistance in the dead spotresistor 59. The resistor I05 may be omitted if desired. Similarly aresistor I66 connecting the wiper 42 to the extremities of winding 40 ofthe potentiometer 20 at conductor 41 is connected in series withresistor 48 and to buss bar 26 to provide for varying thecharacteristics of the speed torque curve of the motor. It iseffectively shunted out as the wiper 42 moves toward one end or theother of the winding 40 and hence is most efiective at small handledisplacements becoming less and less effective as the wiper 42 isdisplaced over wider ranges of the winding 40. Its inclusion in thecircuit is optional also.

A resistor I I0 connected at one extremity to the center tap 4! ofwinding 40 and at the other extremity to conductor 62 and coil I1 isprovided for a maximum speed control limit for the motor apparatus. Itis shunted from the wiper 42 to the center tap of the potentiometerwinding 40 and is adjustable to vary the upper speed limit of the motoroperation through the slewing or high speed switches. At low handledisplacements the resistance of resistors I I0 is high compared with theresistance between the center tap of the potentiometer and the wiper 42and has little efiect on the low end of the speed response curve of themotor. As the resistance of resistance H0 is increased the slope of theresponse curve is similarly changed. At the same time the top or slewingspeed of the motor is raised. As the value of resistor III] isdecreased, the slope of the speed torque curve becomes less and the topspeed of the motor is cut down and the sensitivity of the handle isreduced. This addition to the control circuit is also optional and onlymodifies with resistor I65 and the resistor I06 the speed torquecharacteristic of the apparatus.

It should be understood that the wiper 42 and the switches 30, 3| areoperated simultaneously and throuh suitable means such as a handle ormaster control which is not shown. Similarly the slewing or high speedswitches are actuated at the predetermined ranges of movement of themaster control.

In considering this invention it should be kept in mind that the presentdisclosures are to be illustrative only and the scope of the inventionis to be determined only by the appended claims.

I claim as my invention:

1. In motor control apparatus: a motor whose speed is to be controlled,said motor having an armature and a directional field winding; anenergizing circuit means for said motor adapted to be connected to asource of power and including a circuit closure means operated by a pairof windings; a primary controller adapted to be connected to said sourceof power; first circuit means including said primary controller and oneof said windings, said armature and said directional field windingsconnected across said source of power and adapted to operate saidcircuit closure means to a closed position completing said energizingcircuit 'for said motor upon operation of said primary controller;second circuit means including the other of said windings, a condenserand said circuit closure means connected across said source of power andoperative upon closure of said circuit closure means to energize saidother of said windings to urge said circuit closure means toward theclosed position; a third circuit means including said primarycontroller, said one of said windings, a second condenser, a rectifierand said circuit closure means connected across said source of power andoperative upon closure of said circuit closure means to energize saidone of said windings in an opposite direction from that of said firstcircuit means tending to operate said circuit closure means toward anopen position.

2. In motor control apparatus: a motor whose speed is to be controlled,said motor having an armature and a directional field winding; anenergizing circuit means for said motor adapted to be connected to asource of power and including a circuit closure means operated by a pairof windings; a primary controller adapted to be connected to said sourceof power; first circuit means including said primary controller and oneof said windings, said armature and said directional field windingsconnected across said source of power and adapted to operate saidcircuit closure means to a closed position completing said energizingcircuit for said motor upon operation of said primary controller; secondcircuit means including the other of said windings, a condenser and saidcircuit closure means connected across said source of power andoperative upon closure of said circuit closure means to energize saidother of said windings to urge said circuit closure means toward theclosed position; third circuit means including said primary controller,said one of said windings, a second condenser, a rectifier and saidcircuit closure means connected across said source of power andoperative upon closure of said circuit closure means to energize saidone of said windings in an opposite direction from that of said firstcircuit means tending to operate said circuit closure means toward anopen position, and a resistance capacitance circuit means. connectedacross said source of power when said circuit closure means is in aclosed position and discharging through said one of said windings insuch a direction as to urge said circuit closure means toward an openposition.

3. In motor control apparatus: a motor whose speed is to be controlled,said motor having an armature and a directional field winding; an energizing circuit means for said motor adapted to be connected to asource of power and including a circuit closure means operated by a pairof windings, a primary controller adapted to be connected to said sourceof power; first circuit means including said primary controller and oneof said windings, said armature and said directional field windingsconnected across said source of power and adapted to operate saidcircuit closure means to a closed position completing said energizingcircuit for said motor unon operation of said primary controller; secondcircuit means including the other of said windings and an energizationmodifying means connected across said source of power upon operation ofsaid circuit closure means to a closed position and operative toenergize said other of said windings in one direction to initially urgesuch circuit closure means toward 'said circuit closure position andupon opening of said circuit means to energize said other of saidwindings in an opposite direction to urge said circuit closure meanstoward said open position; third circuit means including said primarycontroller, said one of said windings, a second energization modifyingmeans and said circuit closure means connected across said source ofpower and operative upon closure of said circuit closure means toenergize said one of said windings in an opposite direction tending tourge said circuit closure means toward an open position; an energizationstoring circuit means connected across said supply when said circuitclosure means is operated to a circuit closure position and dischargingthrough said one of said windings in such a direction as to urge saidcircuit closure means toward said open position.

4. In motor control apparatus: a motor whose speed is to be controlled,said motor having an armature and a directional field winding; anenergizing circuit means for said motor adapted to be connected to asource of power and including a circuit closure means operated by a pairof windings; a primary controller adapted to be connected to said sourceof power; first circuit means including said primary controller and oneof said windings, said armature and said directional field windingsconnected across said source of power and adapted to operate saidcircuit closure means to a closed position completing said energizingcircuit for said motor upon operation of said primary controller; secondcircuit means including the other of said windings, and energizationmodifying means and said circuit closure means connected across saidsource of power and operative upon operation oi said circuit closuremeans to a closed position to energize said other of said windings toinitially urge such circuit closure means toward said circuit closure.

position; third circuit means including said primary controller, saidone of said windings, a second energization modifying means and saidcircuit closure means connected across said source of power andoperative upon closure of said circuit closure means to energize saidone of said windings in an opposite direction tending to urge saidcircuit closure means toward an open position; the counter E. M. F.generated by said armature upon energization thereof operating to modifythe effective operation of said primary controller in said first circuitmeans; and an energization storing circuit means connected across saidsupply when said circuit closure means is operated to a circuit closureposition and discharging through said one of said windings in such adirection as to urge said circuit closure means toward said openposition.

5. In motor control ap aratus: a motor whose speed and direction ofrotation is to be controlled, said motor having an armature and a pairof directional field windings, an energizing circuit means for saidmotor connected to said armature and said directional field windingsincluding a circuit closure means for controlling the operation of saidenergizing circuit means, electromagnetic means for operating saidcircuit closure means, an energized primary controlling means, meansconnecting said electromagnetic means to said primary controlling meansof said armature such that said electromagnetic means is energized fromsaid primary controlling means and the counter E. M. F. of saidarmature, further electromagnetic means connected to said circuitclosure means and energized in one direction upon operation of saidcircuit closure means to a circuit closure position to provide snapaction type of operation of said circuit closure means toward saidcircuit closure position. a resistance-capaci tance circuit meansconnected to said first named electromagnetic means and said circuitclosure means and energized upon operation of said circuit closure meansto said closed position for modifying the operation of said circuitclosure means, switching means included in said energizing circuit meansfor said field windings andoperatively substantially simultaneously withthe energization of said first named electromagnetic means, and meansadapted to be operated upon,

a need for operation of said motor for controlling the operation of saidprimary controlling means.

6. In motor control apparatus: a motor whose speed and direction ofrotation is to be controlled, said motor having an armature and a pairof directional field windings, an energizing circuit means for saidmotor connected to said armature and said directional field windingsincluding a circuit closure means for controlling the operation of saidenergizing circuit means, electromagnetic means for operating saidcircuit closure means, an energized primary controlling means, meansconnecting said electromagnetic means to said primary controlling meansof said armature such that said electromagnetic means is energized fromsaid primary controlling means andthe counter E. M. F. of said armature,further electromagnetic means connected to said circuit closure meansand energized upon operation of said circuit closure means to a circuitclosure position to provide positive operation of said circuit closuremeans toward said circuit closure position, a resistance-capacitancecircuit means connected to said first named electromagnetic means andsaid circuit closure means and energized upon operation of said circuitclosure means to said closed position for modifying the operation ofsaid circuit closure means, condenser means connected to said firstnamed electromagnetic means and said circuit closure means modifying theenergization of said first named electromagnetic means upon closure ofsaid circuit closure means for modifying with said furtherelectromagnetic means and said resistance-captio itance circuit meansthe amount of current supplied to said armature in proportion to theoperation of said primary controller, switching means included in saidenergizing circuit means for said field windings and operativelysubstantially simultaneously with the energization of said first namedelectromagnetic means, and means adapted to be operated upon a need foroperation of said motor for controlling the operation of said primarycontrolling means.

'7. In motor control apparatus: a motor whose speed and direction ofrotation is to be controlled, said motor having an armature and a pairof directional field windings, an energizing circuit means for saidmotor connected to said armature and said directional field windingsincluding a circuit closure means for controlling the operation of saidenergizing circuit means, first relay coil for operating said circuitclosure means, an energized primary controlling means, means conmeetingsaid first relay coil to said primary controlling means of said armaturesuch that said first relay coil is energized from said primarycontrolling means and the counter E. M. F. of said armature, a secondrelay coil connected to said circuit closure means and energized uponoperation of said circuit closure means to a circuit closure position toprovide positive operation of said circuit closure means toward saidcircuit closure position, a resistance-capacitance circuit meansconnected to said first named relay coil and said circuit closure meansand energized upon operation of said circuit closure means to saidclosed position for modifying the operation of said circuit closuremeans, condenser means connected to said first named relay coil and saidcircuit closure means modifying the cnergization of said first namedrelay coil upon closure of said circuit closure means for modifying withsaid second relay coil and said resistance-capacitance circuit means theamount of current supplied to said armature in proportion to theoperation of said primary controller, switching means included in saidenergizing circuit means for said field windings and operativelysubstantially simultaneously with the energization of said first namedrelay coil, and means adapted to be operated upon a need for operationof said motor for controlling the operation of said primary controllingmeans.

8. In motor control apparatus: a motor whose speed and direction ofrotation is who controlled,

10 said motor having an armature and a directional field winding, anenergizing circuit means for said motor connected to said armature andsaid directional field winding, circuit closure means included in saidenergizing circuit means for con- 15 trolling the energization of saidarmature, electromagnetic means for operating sald circult closuremeans, an energized primary controller, means connecting saidelectromagnetic means to said primary controller and said armaturesuchso O that an electromagnetic means is energized from said primarycontroller and from the counter E. M. F. of said armature, furtherelectromagnetic means connected to said circuit closure means andenergized upon operation of said cir- 5 cuit closure means to a closedposition "to operate said circuit closure means toward said circuitclosure position for positive closure of said circuit means, andresistance-capacitance circuit means connected to saidfirst namedelectromag- O netic means and said circuit closure means and energizedupon operation of said circuit closure means to a closed position formodifying the operation of said circuit closure means by said H primarycontroller, and manual means operatively connected to said primarycontroller and adapted to operate said controller.v

9. In motor control apparatus: a motor whose speed and direction ofrotation is to be controlled, said motor having an armature and a.directional field winding, an energizing circuit means for said motorconnected to said armature and 'said d1- rectional field winding,circuit closure means included in said energizing circuit means forcontrolling the energization of said armature, electromagnetic means foroperating said circuit closure means, an energized primary controller,means connecting said electromagnetic means to said primary controllerand said armature such that said electromagnetic means is energized 0from said primary controller and from the counter E. M. F. of saidarmature, further electromagnetic means connected to said circuitclosure means and energized upon operation of said circuit closure meansto-a closed position to operate 5 said circuit closure means toward saidcircuit closure position for positive closure of said circuit closuremeans, resistance-capacitance circuit means connected to said firstnamed electromagnetic means and said circuit closure means 0 andenergized upon operation of said circuit closure means to a closedposition for modifying the operation of said circuit closure means bysaid primary controller, condenser means connected to said first namedelectromagnetic means and said circuit closure means modifying theenergization of said first named electromagnetic means upon closure ofsaid circuit closure means for modifying with said furtherelectromagnetic means and said resistance-capacitance circuit 0 meansthe operation of said circuitclosure means in proportion to theoperation of said primary controller, and manual means operativelyconnected to said primary controller and adapted to operate saidcontroller.

75 10, In'motor control apparatus: :a. motor whose speed and directionof rotation is to be controlled, said motor having an armature and adirectional field winding, an energizing circuit means for said motorconnected to said armature and said directional field winding, circuitclosure means included in said energizing circuit means for controllingthe encrgization or said armature, electromagnetic means for operatingsaid circuit closure means, a primary controller connected to andenergized from said energizing circuit means, means connecting saidelectromagnetic means to said primary controller and said armature suchthat said electromagnetic means is energized from said primarycontroller and from the counter E. M. F. of said armature, furtherelectromagnetic means connected to said circuit closure means andenergized upon operation of said circuit closure means to a closedposition to operate said circuit closure means toward said circuitclosure position for positive closure of said circuit closure means, andresistance-capacitance circuit means connected to said first namedelectromagnetic means and said circuit closure means and energized uponoperation of said circuit closure means to a closed position formodifying the operation of said circuit closure means by said primarycontroller, condenser means connected to said first namedelectromagnetic means and said circuit closure means modifyin theenergization of said first named electromagnetic means upon closure ofsaid circuit closure means for modifying with said furtherelectromagnetic means and said resistance-capacitance circuit means theoperation of said circuit closure means in proportion to the operationof said primary controller, switching means connected in parallel withsaid primary controller and to said first named electromagnetic meansand operative to short out said primary controller and apply fullenergization to said first named electromagnetic means, and manual meansoperatively connected to said primary controller and said switchingmeans and adapted to operate said controller over a predetermined rangeof movement before operating said switching means.

11. In a motor control apparatus: a motor whose speed and direction ofrotation is to be controlled, said motor having an armature and a pairof directional field windings, an energizing circuit means for saidmotor connected to said armature and said directional field windings,circuit closure means included in said energizing circuit means forcontrolling the energization of said armature, electromagnetic means foroperating said circuit closure means, an energized primary controller,means connecting said electromagnetic means to said primary controllerand said armature such so that an electromagnetic means is energizedfrom said primary controller, switching means included in saidenergizing circuit means for said directional field windings, furtherelectro magnetic means connected to said circuit closure means andenergized upon operation of said circuit closure means to a closedposition to operate said circuit closure means toward said circuitclosure position for positive closure of said circuit closure means,resistance-capacitance circuit means connected to said first namedelectromagnetic means and said circuit closure means and energized uponoperation of said circuit closure means to a closed position formodifying the operation of said circuit closure means by .said primarycontroller, and manual means operatively connected to said primarycontroller and said switching means and adapted to simulta- 14; neouslyoperate said controller and said switching means.

12. In a motor control apparatus: a motor whose speed and direction ofrotation is to be controlled, said motor having an armature and a pairof directional field windings, an energizing circuit means for saidmotor connected to said armature and said directional field windings,circuit closure means included in said energizing circuit means forcontrolling the energization of said armature, electromagnetic means foroperating said circuit closure means, an energized primary controller,means connecting said electromagnetic means to said primary controllerand said armature such that said electromagnetic means is energized fromsaid primary controller, switching means included in said energizingcircuit means for said directional field windings, furtherelectromagnetic means connected to said circuit closure means andenergized upon operation of said circuit closure means to a closedposition to operate said circuit closure means toward said circuitclosure position for positive closure of said circuit closure means,resistance-capacitance circuit means connected to said first namedelectromagnetic means and said circuit closure means and energized uponoperation of said circuit closure means to a closed position formodifiying the operation of said circuit closure means by said primarycontroller, condenser means connected to said first namedelectromagnetic means and said circuit closure means modiflying theenergization of said first named electromagnetic means upon closure ofsaid circuit closure means for modifiying with said furtherelectromagnetic means and said resistance-capacitance circuit the amountof current supplied to said armature in proportion to the operation ofsaid primary controller, and manual means operatively connected to saidprimary controller and said switching means and adapted tosimultaneously operate said controller and said switching means.

13. In a motor control apparatus: a motor whose speed and direction ofrotation is to be controlled, said motor having an armature and a pairof directional field windings, an energizing circuit means for saidmotor connected to said armature and said directional field windings,circuit closure means included in said energizing circuit means forcontrolling the energization of said armature, electromagnetic means foroperating said circuit closure means, an energized primary controller,means connecting said electromagnetic means to said primary controllerand said armature such that said electromagnetic means is energized fromsaid primary controller, switching means included in said energizingcircuit means for said directional field windings, furtherelectromagnetic means connected to said circuit closure means andenergized upon operation of said circuit closure means to a closedposition to operate said circuit closure means toward said circuitclosure position for positive closure of said circuit closure means,resistancecapacitance circuit means connected to said first namedelectromagnetic means and said circuit closure means and energized uponoperation of said circuit closure means to a closed position formodifying the operation of said circuit closure means by said primarycontroller, further switching devices connected in parallel with saidprimary controller and to said first named electromagnetic means beingoperative to short out said primary controller and apply full energization to said first named electromagnetic means overcoming the effect ofsaid resistance-capacitance circuit of said furthering condenser means,and manual means operatively connected to said primary controller andsaid first and second named switching means and adapted tosimultaneously operate said controller and said first named switchingmeans and after a predetermined range of operation said second namedswitching means.

14. In a motor control apparatus: a motor whose speed is to becontrolled, said motor having an armature and directional fieldwindings, an energizing circuit means for said motor adapted to beconnected to a source of power and including said armature andsaid'field windings, relay means including contact means operated by apair of operating coils, said contact means being included in saidenergizing circuit means in series with armature to control an operationof said energizing circuit means, a primary controller adapted to beenergized from said source of power, means connecting one of said relaycoils to said primary controller and said energizing circuit such thatthe coil is energized from said primary controller and from the counterE. M. F. of said armature, switching means connected to said energizingcircuit means and in a series of relationship with said directionalfield windings for connecting at least on of said field windings in saidenergizing circuit means for each of a pair of operating positions ofsaid switching means, manual means operatively connected to said primarycontroller and said switching means and adapted to simultaneouslyoperate said primary controller and said switching means to vary theenergization of said first of said relay coils and said armature andoperate said switching means to one or the other of the operatingpositions to energize one or the other of said field windings, thesecond of said relay coils being connected to said contact means andenergized upon operation of said contact means to provide for positiveoperation of said contact means toward a closed position, a resistance'capacitance circuit means connected to said first relay coil and to saidcontact means and energized upon operation of said contact means to aclosed position for modifying energization of said first relay coil.

15. In a motor control apparatus: a motor whose speed is to becontrolled, said motor having an armature and directional fieldwindings, an energizing circuit means for said motor adapted to beconnected to a source of power and including said armature and saidfield windings, relay means including contact means operated by a pairof operating coils, said contact means being included in said energizingcircuit means in series with said armature to control an operation ofsaid enerigizing circuit means, a primary controller adapted to beenergized from said source of power, means connecting one of said relaycoils to said primary controller and said energizing circuit such thatthe coil is energized from said primary controller and from the counterE. M. F. of said armature, switching means connected to said energizingcircuit means and in a series or relationship with said directionalfield windings for connecting at least one of said field windings insaid energizing circuit means for each of a pair of operating positionsof said switching means, manual means operatively connected to saidprimary controller and switching means and adapted to simultaneouslyoperate said primary controller andsaid switching means to vary theenergization of said first of said relay coils and said armature andoperate said switching means to one or the other of the operatingpositions to energize one or the other of said field windings, the sec-0nd of said relay coils being connected to said contact means andenergized upon operation of said contact means to provide for positiveoperation of said contact means toward a closed position, aresistance-capacitance circuit means connected to said first relay coiland to said contact means and energized upon operation of said contactmeans to a closed position for modifying energization of said firstrelay coil, and condenser means connected to said first relay coil andsaid contact means in series relation therewith and through aunidirectional current conducting means modifying energization of saidfirst relay coil upon closure of said contact means for modifying withsaid second relay coil and said'resistance-capacitance circuit theamount of current supplied to said armatur in proportion to theoperation of said primary controller.

16. In a motor control apparatus: a motor whose speed is to becontrolled, said motor having an armature and directional fieldwindings, an energizing circuit means for said motor adapted to beconnected to a source of power and including said armature and saidfield windings, relay means including contact means operated by a pairof operating coils, said contact means being included in said energizingcircuit means in series with said armature to control an operation ofsaid energizing circuit means, a primary controller adapted to beenergized from said source of power, means connecting one of said relaycoils to said primary controller and said energizing circuit such thatthe coil is energized from said primary controller and from the counterE. M. F. of said armature, switching means connected to said energizingcircuit means and in a series of relationship with said directionalfield windings for connecting at least one of said field winding-s insaid energizing circuit means for each of a pair of operating positionsof said switching means, manual means operatively connected to saidprimary controller and said switching means and adapted tosimultaneously operate said primary controller and said switching meansto vary the energization of said first of said relay coils and saidarmature and operate said switching means to one or the other of theoperating positions to energize one or the other of said field windings,the second of said relay coils being connected to said contact means andenergized upon operation of said contact means to provide for positiveoperation of said contact means toward a closed position, aresistance-capacitance circuit means connected to said first relay coiland to said contact means and energized upon operation of said contactmeans to a closed position for modifying energization of said firstrelay coil, condenser means connected to said first relay coil and. saidcontact means in series relation therewith and through a unidirectionalcurrent conducting means modifying energization of said first relay coilupon closure of said contact means for modifying with said second relaycoil and said resistance-capacitance circuit the amount of currentsupplied to said armature in proportion to the operation of said primarycontroller, and further switching means connected in parallel with saidprimary controller and to said first relay coil and operative to shortout said primary controller and applying full energization to said firstrelay'coil overcoming the efiect of said resistance-capacitance circuitand said condenser means, said further switching means being connectedto said manual means and operative only after a predetermined amount ofmovement of said manual means.

17. In a motor control apparatus: a motor whose speed and direction ofrotation is to be controlled, said motor having an armature and a pairof directional field windings, an energizing circuit means for saidmotor and connected to said armature and said directional fieldwindings, circuit closure means included in said energizing circuitmeans for controlling the energization of said armature, electromagneticmeans for operating said circuit closure means, an energized primarycontrolling means, means connecting said electromagnetic means to saidprimary controlling means and said armature such that saidelectromagnetic means is energized in part from said primary controller,switching means included in said energizing circuit means for said fieldwindings and operative with the energization of said electromagneticmeans, means operatively connected to said primary controller forcontrolling the operation of the same, further electromagnetic means anda condenser connected to said circuit closure means and said energizingcircuit being energized upon operation of said circuit closure meanstoward a closed circuit to provide for snap action operation of saidcircuit closure means toward said circuit closure position and uponopening of said circuit closure means and discharge of said condenserbeing energized to provide for snap action of said circuit closure meanstoward circuit open position, an energy storing circuit means connectedto said first named electromagnetic means and said circuit closure meansand energized from said energizing circuit means upon operation of saidcircuit closure means to a circuit closure position for modifying theoperation of said cir cuit closure means by said first namedelectromagnetic means.

18. In a motor control apparatus: a motor whose speed and direction ofrotation is to be controlled, said motor having an armature and a pairof directional field windings, an energizing circuit means for saidmotor and connected to said armature and said directional fieldwindings, circuit closure means included in said energizing circuitmeans for controlling the energization of said armature, electromagneticmeans for operating said circuit closure means, an energized primarycontrolling means, means connecting said electromagnetic means to saidprimary controlling means of said armature such that saidelectromagnetic means is energized in part from said primary controller,switching means included in said energizing circuit means for said fieldwindings and operative with the energization of said electromagneticmeans, means operatively connected to said primary controller forcontrolling the operation of the same, further electromagnetic meansconnected to said circuit closure means and said energizing circuit andenergized upon operation of said circuit closure means toward a closedcircuit to provide for post.

tive operation of said circuit closure means toward said circuit closureposition, an energy storing circuit means connected to said first namedelectromagnetic means and said circuit closure means and energised fromsaid energizing circuit means upon operation of said circuit closuremeans to a circuit closure, a position for modifying the operation ofsaid circuit closure means by said first named electromagnetic means,and second energy storing means connected to said first namedelectromagnetic means said circuit closure means and through aunidirectional current conducting device for modifying with said furtherelectromagnetic means and said first said energy storing circuit theamount of current supplied to said armature in proportion to theoperation of said primary controller.

19. In a motor control apparatus: a motor whose speed and direction ofrotation is to be controlled, said motor having an armature and a pan ofdirectional field windings, an energizing circuit means for said motorand connected to said armature and said directional field windings,circuit closure means included in said energizing circuit means forcontrolling the energization of said armature, electromagnetic means foroperating said circuit closure means, primary controlling meansconnected to and energized from said energizing circuit, meansconnecting said electromagnetic means to said primary controlling meansof said armature such that said electromagnetic means is energized inpart from said primary controller, switching means included in saidenergizing circuit means for said field windings and operative with theenergization of said electromagnetic means, means operatively connectedto said primary controller for controlling the operation of the same,further electromagnetic means connected to said circuit closure meansand said energizing circuit and energized upon operation of said circuitclosure means toward a closed circuit to provide for positive oper..ation of said circuit closure means toward said circuit closureposition, an energy storing circuit means connected to said first namedelectromagnetic means and said circuit closure means and energized fromsaid energizing circuit means upon operation of said circuit closuremeans to a circuit closure position for modifying the operation of saidcircuit closure means by said first named electromagnetic means, andsecond energy storing means connected to said first namedelectromagnetic means, said circuit closure means and through aunidirectional current conducting device for modifying with said furtherelectromagnetic means and said first said energy storing circuit theamount of current supplied to said armature in proportion to theoperation of and primary controller, said further switching means beingoperatively connected to said means operating said primary controllerand operated thereby for shunting out said primary controller for apredetermined range of movement of said operating means.

No references cited.

